A Westpac bank manager fleeced her elderly clients out of more than $373,000 and used some of the money to pay for her new kitchen.

Helen Marie Kemp, of Whitby, deceived six customers over four years while working at branches in the northern Wellington suburbs of Tawa and Johnsonville. Between 2009 and 2013, she forged signatures to create phoney loans, credit cards, overdrafts and bank statements in their names.

In July 2011, she used about $42,000 of her ill-gotten gains to buy new appliances and granite countertops for the kitchen in her home in the swanky Porirua suburb. She was caught out only after she went on annual leave and another staff member discovered irregularities with the accounts she was managing.

Kemp pleaded guilty in the Wellington District Court yesterday to nine charges of illegally accessing a computer, forgery, obtaining by deception and using a document.

Crown prosecutor Sally Carter said the six victims were older and vulnerable, the youngest being 59 and the oldest being in their 80s.

Their names have been suppressed. Kemp began taking their money in October 2009 while she was a manager at Westpac's Tawa branch. She manipulated the bank's computer and forged the signatures of one couple so she could take out a $60,000 loan on their property, registering their mortgage as security.

She took $20,000 for herself and used the rest of the money to repay the loan.

By 2010, she was a manager at Westpac's Johnsonville branch and had extended the loan several times to $135,000. She also took out a credit card on their account.

She also preyed on a couple who opened their first account with Westpac in 1967. They had amassed nearly $200,000 in term deposits and accounts, of which Kemp swiped more than half over a period of two years.

The fraud was discovered when one of the couple contacted the bank because they had not been offered any reinvestment advice about one of their term deposits.

Kemp opened a $3000 overdraft on a closed account of another of her victims, then withdrew money from it. She dipped into the bank account of her final victim 132 times, taking more than $39,000.

The victim had praised Kemp for helping her do her banking over the phone but it turned out she was being given false statements, Carter said.

The fraud was revealed when the victim called Westpac while Kemp was on annual leave, to ask about breaking a $20,000 term deposit. When another staff member accessed the computer, they discovered the money was no longer there.

Westpac reimbursed everyone affected and is seeking more than $373,000 in reparation from Kemp.